Early career Adiyiah began his career in the Feyenoord Academy, which he joined when he was only 10 years old. He spent seven years in Gomoa Fetteh, where the Academy is based, before transferring to Heart of Lions in January 2007. After making his debut in the Ghana Premier League, he went on to score 13 goals in 24 appearances for the club based in Kpandu, finishing second in the scoring list. At the end of the 2007–08 season he was named Most Exciting Player of the league. Fredrikstad (2008–2010) In August 2008, Adiyiah made the move to Europe, being signed by Norwegian top flight club Fredrikstad for a fee of only £100k (approx. €125k as of that date). He made his debut for the club in an away match against Aalesund, on 30 August. Despite going scoreless in four appearances during the 2008 season, he did impress Fredrikstad’s coaching staff, as the team finished second in the league. The following season he scored twice during the training camp, but has not scored in the four league matches he appeared. He also made his debut in the Europa League, in the second leg of the third qualifying round against Lech Pozna?. Milan (2010–present) In late October 2009, after impressing in the U-20 World Cup, Adiyiah was reported to be close to joining Serie A club Milan. Speculation increased as Fredrikstad announced they had received a bid €500k for the young striker from a big European club. The rumour was eventually confirmed by Milan CEO Adriano Galliani on 1 November, and six day later the Ghanaian signed his new contract, as he had passed routine medical examinations. The move was ratified on 2 January 2010, the first day of the winter transfer window. However Adiyiah was still not able to play, since he was called-up by the Ghana national team to take part in the African Nations Cup. Upon his return, a month later, he also secured an Italian work permit, which he was still lacking, thus becoming definitively eligible to play.Despite this, he was never selected by head coach Leonardo during the remainder of the 2009–10 season. International career Adiyiah has been called-up for the Black Satellites since 2008, making his debut on 30 March, in a match against Niger, and also participating in the WAFU U-20 Championship. In October 2009, he took part in the U-20 World Cup held in Egypt. As the team went on winning the trophy, he was awarded the Golden Shoe for the topscorer with 8 goals in 7 games and was also named the Most Valuable Player of the tournament. Adiyiah earned his first call-up with the Black Stars on 3 November 2009, shortly after the U-20 triumph, for a World Cup qualification match against Mali, to be played on 15 November. However he was left as an unused substitute. He did make his senior debut three days later though, in a friendly against Angola. In January 2010, he was part of the Ghanaian team that reached the final at the African Nations Cup. Despite making only two substitute appearances, he showed glimpses of a player for the future. In June of the same year, he was called-up to take part in the upcoming World Cup, to be played in South Africa.

In February 2015, Adiyiah signed for Nakhon Ratchasima F.C. side Nakhon Ratchasima F.C